| Item Type: |
Ph.D. Thesis |
| Type of entry: |
Primary publication |
| Title: |
Preparation, characterization and physical properties of new compounds in the system Ln2O3 - ReO2 – ½ Re2O7 (Ln=lanthanides or yttrium) |
| Language: |
English |
| Referees: |
Galy, Prof. Dr. Jean |
| Advisors: |
Fuess, Prof. Dr. Hartmut |
| Date: |
18 June 2004 |
| Place of Publication: |
Darmstadt |
| Date of oral examination: |
16 July 2003 |
| Abstract: |
The aim of this thesis has been the preparation of new phases in the system rare-earth – rhenium – oxygen (Ln2O3 - ReO2 – ½ Re2O7, with Ln = Lanthanides and Yttrium), the solution of their crystal structures with X-ray or neutron diffraction and their physical properties as conductivity or magnetic behaviour. Detailed descriptions are given for the preparation methods of new compounds with the compositions (Ln0.81Re0.19)3O5.64, Ln6ReO12, Ln5Re2O12, Ln3ReO8, Y7ReO14-d , Y3-xRe1+xO8 and Re3O10 and their structure solutions using powder or single crystal data. Measurements of the magnetization yielded deviations from the ideal paramagnetic behaviour at low temperatures for all compounds Ln6ReO12 (Ln = Ho, Er, Tm), Ln5Re2O12 (Ln = Er), Ln3ReO8 (Ln = Gd – Lu) and Y7ReO14-d . Only Yb5Re2O12 shows a significant deviation already at 100 K, Lu6ReO12 shows paramagnetic behaviour down to 1.7 K. Resistivity measurements has been carried out for the compounds Ln3ReO8 (Ln = Eu, Dy,Y). All samples appeared as semi conductors with band gaps of 192.2 meV for Eu3ReO8, 159.7 meV for Dy3ReO8 and 157.4 meV for Y3ReO8. |
| Alternative Abstract: |
| Alternative Abstract | Language |
|---|
Zielsetzung dieser Arbeit war die Darstellung neuer ternaerer Phasen im System Seltenerde-Rhenium-Sauerstoff (Ln2O3 - ReO2 – ½ Re2O7, mit Ln = Lanthanide und Yttrium), die Loesung ihrer Kristallstrukturen mit Roentgen- oder Neutronenbeugung sowie die Untersuchung ihrer physikalischen Eigenschaften wie Leitfaehigkeit oder magnetisches Verhalten. Im einzelnen beschrieben werden die Darstellungen neuer Verbindungen mit den Zusammensetzungen (Ln0.81Re0.19)3O5.64, Ln6ReO12, Ln5Re2O12, Ln3ReO8, Y7ReO14-d , Y3-xRe1+xO8 und Re3O10 und deren Strukturloesungen aus Pulver- oder Einkristalldaten. Magnetisierungsmessungen ergaben bei allen Proben der Zusammensetzungen Ln6ReO12 (Ln = Ho, Er, Tm), Ln5Re2O12 (Ln = Er), Ln3ReO8 (Ln = Gd – Lu) und Y7ReO14-d erst bei tiefen Temperaturen Abweichungen vom paramagnetischen Verhalten. Yb5Re2O12 hingegen zeigt dieses Verhalten bereits ab ca. 100 K, Lu6ReO12 zeigt erwartungsgemaess paramagnetisches Verhalten bis 1.7 K. Widerstandsmessungen an Proben vom Typ Ln3ReO8 (Ln = Eu, Dy,Y) ergaben typisches Halbleiterverhalten mit Bandluecken von 192.2 meV fuer Eu3ReO8, 159.7 meV fuer Dy3ReO8 und 157.4 meV fuer Y3ReO8. | German |
|
| Uncontrolled Keywords: |
Seltenerd-Rhenium-Oxide, Strukturloesung, Magnetische Eigenschaften, Leitfaehigkeit |
| Alternative keywords: |
| Alternative keywords | Language |
|---|
| Seltenerd-Rhenium-Oxide, Strukturloesung, Magnetische Eigenschaften, Leitfaehigkeit | German | | Rare-earth rhenium oxides, structure solution, magnetic properties, conductivity | English |
|
| URN: |
urn:nbn:de:tuda-tuprints-4511 |
| Classification DDC: |
500 Science and mathematics > 540 Chemistry |
| Divisions: |
11 Department of Materials and Earth Sciences |
| Date Deposited: |
17 Oct 2008 09:21 |
| Last Modified: |
08 Jul 2020 22:49 |
| URI: |
https://tuprints.ulb.tu-darmstadt.de/id/eprint/451 |
| PPN: |
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